Jellyfish are usually either male or female, though some can be hermaphrodites (possessing both male and female reproductive organs).
Most jellyfish species reproduce sexually. Adult jellyfish, in their medusa stage, release sperm and eggs into the surrounding water. Fertilization then occurs externally, meaning outside the jellyfish's body. The fertilized eggs develop into larvae.
However, jellyfish also have the ability to reproduce asexually, particularly in their polyp stage. This process involves budding or fission, where the polyp creates clones of itself.
Therefore, determining if "a" jellyfish is a boy or a girl depends on the specific jellyfish in question and its species. It will generally be one or the other.
